Game of Thrones star Lena Headey has opened up about her battle with anxiety and depression, in a refreshingly candid conversation about mental health with fans on Twitter yesterday.

Responding to someone who asked whether she ever felt insecure, the actress – who has earned millions of dollars for her depiction of Cersei Lannister in the hit HBO series – replied: “I overthink for sure. I am familiar with depression. I get HUGE anxiety (always fun) Insecure, not really.”

She then expanded on how she has coped, saying: “Anxiety is a beast. You have to talk to beasts. Release them back into the wild. Easier said than done I know but still. Good to Practice.”

The British actress shot to fame after first appearing as Cersei, one of GoT’s most iconic and deliciously evil yet complex characters, in 2011.

She has since won multiple award nominations and widespread critical acclaim but admits she is vulnerable to being tricked into thinking: “You don't have enough. You're not enough. Pretty enough. Thin enough. Rich enough. Capable enough. Successful enough.”

“Well here's the truth,” she added. “You are enough... in fact you're who you're meant to be which is BEAUTIFUL… Let's REMEMBER that. Don't be afraid to let someone really SEE you. Magic happens when you are vulnerable and truthful and HUMAN.”

In opening up about her own personal battles with mental illness in such an honest an public way, the mum-of-two encouraged others to do the same.

“Try one conversation face to face without hiding your true self. You'll feel terrified maybe .. for a second .. and then BOOM … Drop the Mike. You fucking did it. Swagger home with some complex fucked up shared human realness.”

Headey is not the first Hollywood star to open up about her battle with mental illness.

The past few years have seen an increasing number of public figures talk freely about their own experiences of anxiety and depression, in an effort to encourage others to do the same and blitz the stigma that is still sometimes associated with mental illness.

Last year, Winona Ryder – one of the first celebrities to discuss her experiences of depression back in 1999 – said she wished people would stop being judged for exposing themselves.

“I’m so sick of people shaming women for being sensitive or vulnerable. It’s so bizarre to me,” she said. “I don’t regret opening up about what I went through [with depression], because, it sounds really cliché, but I have had women come up to me and say, ‘It meant so much to me.’ It means so much when you realize that someone was having a really hard time and feeling shame and was trying to hide this whole thing.”

Lena Dunham is another vocal advocate of speaking openly about mental health issues, a mission that has led her to criticise the way popular culture depicts women on medication for depression or anxiety.

“Lately I've been noticing that nearly every pop cultural image we see of a woman on psychiatric medication is that of an out-of-control, exhausting and exhausted girl who needs help," she wrote on Instagram last year.

“But guess what? Most women on meds are women who have been brave enough to help themselves.”

One in four people in the UK will suffer a mental health problem every year. For more information and support visit mind.org.uk.